<ng-template>
  <thead>
    <tr>
      <th *ngFor="let header of headers">
        <a (click)="sort.emit(header)">
          {{ header.label }}&nbsp;<span [ngClass]="{'glyphicon-triangle-top': (header.sort === 'asc'), 'glyphicon-triangle-bottom': (header.sort === 'desc')}" class="glyphicon" *ngIf="header.sort"></span>
        </a>
      </th>
    </tr>
  </thead>
</ng-template>
